1. Field of the Invention
The invention relates to a driver circuit, to a method for operating a driver circuit, and to a use of a current mirror.
2. Description of the Background Art
Japanese Patent Document No. JP 2001 036187 A discloses a driver circuit for a laser diode. The load current to be driven is generated by a differential pair of transistors and subsequent amplification with a current mirror.
European Patent No. EP 1 478 063 D1, which corresponds to U.S. Pat. No. 7,145,929, and which discloses a driver circuit for operating an electronic component. The driver circuit drives a current which is switched in a controlled manner between at least two discrete current strengths. The driver circuit has a current mirror circuit with a reference transistor and with another transistor connected to the output. The driver circuit in this case is formed to realize a frequency-dependent mirror factor. As a result, the effective collector base capacitance of the driver circuit is reduced. To this end, the additional transistor connected to the output is connected in series with a resistor and an inductor.
German Patent Application No. DE 10 2005 022 612 A1, which corresponds to U.S. Publication No. 20060255838, and which discloses a driver circuit for electronic components. In this case, an amplifier is provided which generates a control signal from a reference signal. Furthermore, a driver current mirror and a control signal switch arranged between the amplifier and the driver current mirror are provided. The control signal switch connects the amplifier optionally with the driver current mirror or separates these. The amplifier is connected to a compensation circuit, which together with the amplifier provides a regulated current source.
U.S. Patent Application No. 20070253313 A1 discloses a laser driver and a method for driving the laser, as well as a recording and reading device. European Patent No. EP 0 810 700 A2, which corresponds to U.S. Pat. No. 5,701,060, also discloses a driver circuit for a laser diode. Damping circuits connected in series reduce ringing on the laser diode current, the ringing being caused by three different resonances which are coupled together.